Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [121]-132).

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographic references (leaves [211]-223).

Thesis (Ph. D.)--Illinois State University, 1981. / Title from title page screen, viewed March 28, 2005. Dissertation Committee: Fritz Schwalm (chair), Arlan Richardson, Mathew Nadakavukaren, Harry Huizinga, Glenn Collie. Includes bibliographical references (leaves 175-186) and abstract. Also available in print.

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Maria A. Croyle. Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1983. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 180-202).

Bibliography: leaves 103-129. The study isolates a 920 bp proximal promoter segment of the CYP2H2 gene from a chicken genomic clone.

Interest has remained very intense during the last two decades on the heme-containing monooxygenase system, cytochrome P-450. The P-450 hemoproteins are widely distributed in nature and engage in oxygenation of a wide variety of substrates according to the reaction, R-H + 0₂ + 2H⁺+ 2e⁻ → R-OH + H₂0 where R-H represents an unactivated carbon-hydrogen bond. Investigations on binding of small gas molecules such as CO and 0₂ to the P-450 enzymes are important not only in understanding various aspects of monooxygenation but also in developing protein-free model systems that can mimic the catalytic properties of P-450. This thesis describes gas binding studies carried out on cytochrome P-450cam. A procedure is given for growing the bacterium Pseudomonas putida strain 786 from which soluble, camphor hydroxylating P-450 enzyme is isolated and purified. The binding of CO to the stoichiometrically reduced substrate-free enzyme at different temperatures was studied using a standard spectrophotometric procedure. From these experimental data, the thermodynamic parameters ΔH⁰ and ΔS⁰ were calculated for the reaction, (P-450)Fe(II) + CO ⇌ (P-450)Fe(11)-C0 . Attempts to determine such thermodynamic parameters for the binding of dioxygen to the substrate-bound P-450 enzyme were not successful. On comparison of the determined thermodynamic parameters for the substrate-free system with the literature values for substrate-bound enzyme, hemoglobin, myoglobin and P-450 model systems, it is concluded that the substrate molecule was bonded in the immediate vicinity of the active-site thereby lowering the CO affinity to the substrate-bound system. / Science, Faculty of / Chemistry, Department of / Graduate

Le cytochrome P450 3A4 hépatique humain (CYP3A4) est le cytochrome P450 le plus abondant. Celui-ci est impliqué dans la dégradation de plus de 50% des médicaments que nous absorbons. Les cytochromes P450 forment une grande famille d'enzymes, caractérisée par la présence d'un hème au site actif, que l'on retrouve chez tous les organismes vivants. La réaction générale catalysée par les cytochromes P450 est une réaction d'oxygénation de substrats qui consomme de l'oxygène et du NADPH. L'étude du CYP3A4 nous a permis de constater que le site actif de cette enzyme est très sensible à la pression et qu'il était essentiel de privilégier un mode de lyse des cellules exprimant le CYP3A4 aux ultra-sons. L'expression en grande quantité du polypeptide a été réussie par l'utilisation en combinaison du vecteur d'expression pET-30a et de la souche Escherichia coli C41 (DE3). Les premières études de spectroscopie de résonance Raman du CYP3A4 purifié nous ont permis d'assigner le mode de vibration VFe-co comme étant situé à 476 cm"1 . De plus les spectres de résonance Raman dans la région des basses fréquences n'ont démontré qu'un très léger déplacement du mode VFeco lors de l'ajout des substrats imipramine et nifédipine. Ce résultat est compatible avec le fait que le site actif du CYP3A4 est flexible et relativement grand de sorte que la molécule de CO liée à Thème n'est presque pas été affectée par l'ajout de ces substrats.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 173-184).

Thesis (Ph. D.)--Uppsala universitet, 2004. / Available also in print. Description based on contents viewed Aug. 12, 2004; title from title screen. Includes bibliographical references (p. 69-77).